diff --git a/ognibuild/buildsystem.py b/ognibuild/buildsystem.py
index fd40ee6..f33dd59 100644
--- a/ognibuild/buildsystem.py
+++ b/ognibuild/buildsystem.py
@@ -221,7 +221,6 @@ import sys
 
 script_name = %(script_name)s
 
-save_argv = sys.argv.copy()
 g = {"__file__": script_name, "__name__": "__main__"}
 try:
     core._setup_stop_after = "init"
diff --git a/ognibuild/debian/apt.py b/ognibuild/debian/apt.py
index 7c168aa..2451a2b 100644
--- a/ognibuild/debian/apt.py
+++ b/ognibuild/debian/apt.py
@@ -28,7 +28,7 @@ from .. import DetailedFailure, UnidentifiedError
 from ..session import Session, run_with_tee, get_user
 from .file_search import (
     FileSearcher,
-    AptCachedContentsFileSearcher,
+    get_apt_contents_file_searcher,
     GENERATED_FILE_SEARCHER,
     get_packages_for_paths,
 )
@@ -76,7 +76,7 @@ class AptManager(object):
     def searchers(self):
         if self._searchers is None:
             self._searchers = [
-                AptCachedContentsFileSearcher.from_session(self.session),
+                get_apt_contents_file_searcher(self.session),
                 GENERATED_FILE_SEARCHER,
             ]
         return self._searchers
@@ -90,7 +90,6 @@ class AptManager(object):
 
     def get_packages_for_paths(self, paths, regex=False, case_insensitive=False):
         logging.debug("Searching for packages containing %r", paths)
-        # TODO(jelmer): Make sure we use whatever is configured in self.session
         return get_packages_for_paths(
             paths, self.searchers(), regex=regex, case_insensitive=case_insensitive
         )
diff --git a/ognibuild/debian/file_search.py b/ognibuild/debian/file_search.py
index d0d9ff4..b7054f5 100644
--- a/ognibuild/debian/file_search.py
+++ b/ognibuild/debian/file_search.py
@@ -21,11 +21,13 @@ from datetime import datetime
 from debian.deb822 import Release
 import os
 import re
+import subprocess
 from typing import Iterator, List
 import logging
 
 
 from .. import USER_AGENT
+from ..session import Session
 
 
 class FileSearcher(object):
@@ -158,7 +160,68 @@ def load_apt_cache_file(url, cache_dir):
     raise FileNotFoundError(url)
 
 
-class AptCachedContentsFileSearcher(FileSearcher):
+class AptFileFileSearcher(FileSearcher):
+
+    CACHE_IS_EMPTY_PATH = '/usr/share/apt-file/is-cache-empty'
+
+    def __init__(self, session: Session):
+        self.session = session
+
+    @classmethod
+    def has_cache(cls, session: Session) -> bool:
+        if not os.path.exists(session.external_path(cls.CACHE_IS_EMPTY_PATH)):
+            return True
+        try:
+            session.check_call([cls.CACHE_IS_EMPTY_PATH])
+        except subprocess.CalledProcessError as e:
+            if e.returncode == 1:
+                return True
+            raise
+        else:
+            return False
+
+    @classmethod
+    def from_session(cls, session):
+        logging.info('Using apt-file to search apt contents')
+        if not os.path.exists(session.external_path(cls.CACHE_IS_EMPTY_PATH)):
+            from .apt import AptManager
+            AptManager.from_session(session).install(['apt-file'])
+        if not cls.has_cache(session):
+            session.check_call(['apt-file', 'update'], user='root')
+        return cls(session)
+
+    def search_files(self, path, regex=False, case_insensitive=False):
+        args = []
+        if regex:
+            args.append('-x')
+        else:
+            args.append('-F')
+        if case_insensitive:
+            args.append('-i')
+        args.append(path)
+        try:
+            output = self.session.check_output(['/usr/bin/apt-file', 'search'] + args)
+        except subprocess.CalledProcessError as e:
+            if e.returncode == 1:
+                # No results
+                return
+            if e.returncode == 3:
+                raise Exception('apt-file cache is empty')
+            raise
+
+        for line in output.splitlines(False):
+            pkg, path = line.split(b': ')
+            yield pkg.decode('utf-8')
+
+
+def get_apt_contents_file_searcher(session):
+    if AptFileFileSearcher.has_cache(session):
+        return AptFileFileSearcher.from_session(session)
+
+    return RemoteContentsFileSearcher.from_session(session)
+
+
+class RemoteContentsFileSearcher(FileSearcher):
     def __init__(self):
         self._db = {}
 
@@ -268,12 +331,12 @@ class GeneratedFileSearcher(FileSearcher):
         with open(path, "r") as f:
             for line in f:
                 (path, pkg) = line.strip().split(None, 1)
-                self._db[path] = pkg
+                self._db.append(path, pkg)
 
     def search_files(
         self, path: str, regex: bool = False, case_insensitive: bool = False
     ) -> Iterator[str]:
-        for p, pkg in sorted(self._db.items()):
+        for p, pkg in self._db:
             if regex:
                 flags = 0
                 if case_insensitive:
@@ -290,16 +353,16 @@ class GeneratedFileSearcher(FileSearcher):
 
 # TODO(jelmer): read from a file
 GENERATED_FILE_SEARCHER = GeneratedFileSearcher(
-    {
-        "/etc/locale.gen": "locales",
+    [
+        ("/etc/locale.gen", "locales"),
         # Alternative
-        "/usr/bin/rst2html": "python3-docutils",
+        ("/usr/bin/rst2html", "python3-docutils"),
         # aclocal is a symlink to aclocal-1.XY
-        "/usr/bin/aclocal": "automake",
-        "/usr/bin/automake": "automake",
+        ("/usr/bin/aclocal", "automake"),
+        ("/usr/bin/automake", "automake"),
         # maven lives in /usr/share
-        "/usr/bin/mvn": "maven",
-    }
+        ("/usr/bin/mvn", "maven"),
+    ]
 )
 
 
@@ -322,6 +385,7 @@ def get_packages_for_paths(
 
 def main(argv):
     import argparse
+    from ..session.plain import PlainSession
 
     parser = argparse.ArgumentParser()
     parser.add_argument("path", help="Path to search for.", type=str, nargs="*")
@@ -334,7 +398,7 @@ def main(argv):
     else:
         logging.basicConfig(level=logging.INFO)
 
-    main_searcher = AptCachedContentsFileSearcher()
+    main_searcher = get_apt_contents_file_searcher(PlainSession())
     main_searcher.load_local()
     searchers = [main_searcher, GENERATED_FILE_SEARCHER]